<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
<style>
    .progress{
        width: 400px;
        height: 25px;
        border-radius: 50px;
        background-color: rgb(7, 7, 7);
        box-sizing: border-box;
        margin-bottom: 30px;
    }
    .inner{
        width: 50%;
        height: 25px;
        border-radius: 50px;
        text-align: right;
        position: relative;
        background-color: blue;
        background-size: 20px 20px;
        box-sizing:border-box;
        transition: all 1s;
    }
    .inner span{
        position: absolute;
        right: -20px;
        bottom: -25px;
    }
</style>
</head>
<body>
    <div id="app">
        <div class="progress">
            <div class="inner" :style="{width:percent + '%'}">
                <span>{{percent}}%</span>
            </div>
        </div>
        <button @click="percent = 25">设置25%</button>
        <button @click="percent = 50">设置50%</button>
        <button @click="percent = 75">设置75%</button>
        <button @click="percent = 100">设置100%</button>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue@2.7.16/dist/vue.js"></script>
    <script>
        const app = new Vue({
            el:'#app',
            data:{
                percent:80
            },
        })
    </script>
</body>
</html>